Procedures such as limb lengthening used to address congenital or traumatic conditions may include an orthopedic osteotomical procedure such as a high tibial osteotomy (HTO). For example, an HTO procedure may be used to treat patients who suffer from a variety of ailments including varus or valgus deformities; that is, abnormal positions of a bone of the leg or foot. This procedure may be used to adjust cartilage wear patterns and/or the distribution of stress along the tibial and knee areas. Performing valgus or varus correction typically adjusts the angulation of a tibial bone and may, in many cases, delay or eliminate the need to replace a joint such as the knee.
Proper adjustment of limb angulation desirably includes adjustment of the bone while the bone is healing. External stabilization or fixation devices are often used to compress and properly align an osteotomy during the healing process. Multiple bone screws, wires and/or pins are often used to provide compression or to attach an external fixation device which provides compression, prevents displacement of bone or tissue fragments, and supports the bone or tissue fragments during healing. These screws, wires and/or pins may be placed through one or both cortices of bone to properly position and align the osteotomy.
Some conventional fixation devices may be used to adjustably secure a first bone portion above an osteotomy in a position relative to a second bone portion below the osteotomy. Unfortunately, some of these devices may require physician intervention for adjustment, and/or may not allow functional use of the recovering limb while the limb is healing. For example, these devices may impair a patient""s ability to walk. Furthermore, many of these devices may impair a physician""s ability to monitor the healing process and/or access the area surrounding the osteotomy. For example, some conventional fixation devices may block or limit radiographic, ultrasonic and/or visual examination of a treatment site.
In addition, some of these devices include a center of rotation that is generally aligned with a center of the tibia. These devices may require additional time for a separate distraction of the bone before the angulation adjustment process may begin, which may result in an extended treatment period. Moreover, these devices may in some cases be used to angulate a tibia with an osteotomy that is not aligned with an adjustment angle of the fixation device. Such misalignment may not provide an optimal level of angulation and/or control thereof.
From the foregoing, it may be appreciated that a need has arisen for providing an improved high tibial osteotomy device. In accordance with the teachings of the present invention, an apparatus and method are provided that substantially reduce. or eliminate disadvantages and problems of conventional external fixation devices.
One aspect of the present invention is represented by a high tibial osteotomy apparatus. The apparatus preferably includes a stabilizing portion adapted to be externally coupled to an anterior portion of a tibial bone. The apparatus may also include an angulation portion adapted to be externally coupled to another anterior portion of the tibial bone and coupled to the stabilizing portion. The angulation portion may be selectively adjustable to angulate a portion of the tibial bone about a center of rotation offset from a center of the tibial bone following an osteotomical procedure on the tibial bone.
Another aspect of the present invention includes an osteotomy guide for placement of an osteotomy. The osteotomy guide has a generally rigid member adapted to be releasably coupled to an external fixation device. The osteotomy guide may also include a receptacle disposed in the member. The receptacle is preferably adapted to receive a plurality of instruments to be used in an osteotomical procedure on a tibial bone.
The present invention provides several important advantages. Various embodiments of the invention may have none, some, or all of these advantages. The invention may permit a variety of monitoring activities. For example, the invention includes a window that allows access and/or visual inspection of the osteotomy. In some applications, the window may include materials that do not obstruct one or more imaging wavelengths. For example, the window may include radiolucent material that is relatively transparent to x-rays. The invention may be secured to an anterior portion of a tibial bone, permitting functional use of the recovering limb while the limb is healing. The invention includes an center of rotation offset from a center of the tibial bone. Such an advantage may reduce or eliminate the need for a separate distraction period to avoid bone impingement before beginning the process of angulation adjustment. For example, the invention may eliminate the need to wait for lengthening to be performed before angulation commences. That is, angulation may commence without waiting the approximately seven to ten days typically required for a separate lengthening or distraction period.
The invention may also allow improved control over conventional methods. For example, the invention allows a patient to perform incremental angulation adjustments. These incremental adjustments desirably promote angulation while reducing the risk of consolidation or solidification of the bone. Such an advantage also may reduce the overall treatment time and/or improve the control in angulation.
The invention may also permit adjustments to be performed so that an osteotomy may be properly compressed. The invention also provides for flexibility in pin placement. The invention may also be used for treatment for both a patient""s left and the right limbs.
The invention may also provide guidance to a physician in performing an osteotomy. For example, the invention may allow proper alignment of the osteotomy with a center of rotation. Such an advantage may improve the control and accuracy of the angulation adjustment process.